Manufacturing method of sensing module for optical fingerprint sensor

ABSTRACT

A manufacturing method of a sensing module for an optical fingerprint sensor is provided. A plurality of photo detectors are formed in a light sensing layer. The photo detectors are arranged in a sensing array. A plurality of collimators are formed in a light filter layer. The collimators are divided into a plurality of collimator groups corresponding to the photo detectors. The collimator groups are arranged in a collimator group array. The light sensing layer is attached to the light filter layer so that the light filter layer is disposed on the light sensing layer and the collimator group array of the light filter layer is aligned with the sensing array of the light sensing layer. Each of the collimator groups corresponds to one of the photo detectors, and aligned with and disposed above the corresponding photo detector. Each of the collimator groups comprises the same number of collimators arranged in a specific pattern.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/519,879, filed on Jun. 15, 2017, and U.S. Provisional Application No.62/621,192, filed on Jan. 24, 2018, and is a divisional of U.S.application Ser. No. 16/007,857, filed on Jun. 13, 2018, the entirety ofwhich are incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to an optical fingerprint sensor, and moreparticularly to an optical fingerprint sensor with a specific collimatorpattern.

Description of the Related Art

In recent years, biological identification technology has becomeincreasingly mature, and different biological features can be used foridentifying users. Since the recognition rate and accuracy offingerprint identification technology are better than those of otherbiological feature identification technologies, fingerprintidentification and verification is used extensively in variousapplications.

Fingerprint identification and verification technology detects a user'sfingerprint image, captures fingerprint data (for example, featurepoints) from the fingerprint image, and stores the fingerprint data tothe memory as a template, or directly stores the fingerprint image.Thereafter, during verification, the user presses or swipes a finger onor over the fingerprint sensor so that a fingerprint image can be sensedand fingerprint data thereof captured. Then, the fingerprint data iscompared with the template. If the two match, then the user's identityis verified.

FIG. 1 shows a conventional optical fingerprint sensor 1. In aconventional optical fingerprint sensor 1, the light-emitting units Cellof the panel module 51, the photo detectors 26 of the sensing module 11and the collimators 36 are equal in number. Each photo detector 26 iscorresponding to a single collimator 36, and receives the light throughthe single corresponding collimator 36. The collimators 36 arerespectively aligned with the transparent zones Z2 of the light-emittingunits Cell in the panel module 51 so as to prevent the collimators 36from being partially or entirely covered by the non-transparent zones Z1of the light-emitting units Cell. Otherwise, light may not pass throughthe collimators and then reach the photo detectors 26 below thecollimators 36. Thus, in the manufacturing process of a conventionaloptical fingerprint sensor 1, when the sensing module 11 is beingattached to the panel module 51, the photo detectors 26 of the sensingmodule 11 have to be respectively aligned with the transparent zones Z2of the light-emitting units Cell of the panel module 51. When thesensing module 11 is being fabricated, the photo detectors 26 also haveto be respectively aligned with the collimators 36 so as to prevent thecollimators 36 from being partially or entirely covered by thenon-transparent zones Z1 of the panel module 51. Accordingly, thereflected light may pass through the collimators, and the photodetectors 26 may receive the light emitted by the light-emitting unitsCell and reflected by the user's finger.

BRIEF SUMMARY OF THE INVENTION

Optical fingerprint sensors and manufacturing methods of a sensingmodule thereof are provided. An embodiment of an optical fingerprintsensor is provided. The optical fingerprint sensor includes a sensingmodule. The sensing module includes a light sensing layer and a lightfilter layer disposed above the light sensing layer. The light sensinglayer includes a plurality of photo detectors arranged in a sensingarray. The light filter layer includes a plurality of collimators. Thecollimators are divided into a plurality of collimator groupscorresponding to the photo detectors, and the number of the collimatorgroups is equal to the number of photo detectors. In each of thecollimator groups, the collimators form a specific pattern and aredisposed above the corresponding photo detector. Each of the photodetectors receives reflected light from the user's finger through thecollimators of the corresponding collimator group.

Furthermore, an embodiment of a manufacturing method of a sensing modulefor an optical fingerprint sensor is provided. A plurality of photodetectors are formed in a light sensing layer, and the photo detectorsare arranged in a sensing array. A plurality of collimators are formedin a light filter layer, and the collimators are divided into aplurality of collimator groups corresponding to the photo detectors. Thecollimator groups are arranged in a collimator group array. The lightsensing layer is attached to the light filter layer so that the lightfilter layer is disposed on the light sensing layer and the collimatorgroup array of the light filter layer is aligned with the sensing arrayof the light sensing layer. Each of the collimator groups corresponds toone of the photo detectors, and aligned with and disposed above thecorresponding photo detector. Each of the collimator groups comprisesthe same number of collimators arranged in a specific pattern.

Moreover, another embodiment of an optical fingerprint sensor isprovided. The optical fingerprint sensor includes a sensing module. Thesensing module includes a light sensing layer and a light filter layerdisposed above the light sensing layer. The light sensing layer includesa plurality of photo detectors arranged in a sensing array. The lightfilter layer includes a plurality of collimators. The collimators aredivided into a plurality of first collimator groups with a first patternand a plurality of second collimator groups with a second pattern. Thetotal number of first and second collimator groups is equal to thenumber of photo detectors. The first and second collimator groups arearranged in a collimator group array, and aligned with the photodetectors in the sensing array. The photo detectors receive reflectedlight from the user's finger through the collimators of thecorresponding first or second collimator groups.

Furthermore, another embodiment of a manufacturing method of a sensingmodule for an optical fingerprint sensor is provided. A plurality ofphoto detectors are formed in a light sensing layer, and the photodetectors are arranged in a sensing array. A plurality of collimatorsare formed in a light filter layer, and the collimators are divided intoa plurality of first collimator groups with a first pattern and aplurality of second collimator groups with a second pattern. The firstand second collimator groups are arranged in a collimator group array.The light sensing layer is attached to the light filter layer so thatthe light filter layer is disposed above the light sensing layer and thecollimator group array of the light filter layer is aligned with thesensing array of the light sensing layer. Each of the first and secondcollimator groups corresponds to one of the photo detectors, and isaligned with and disposed above the corresponding photo detector. Thetotal number of the first and second collimator groups is equal to thenumber of photo detectors.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 shows a conventional optical fingerprint sensor;

FIG. 2 shows an optical fingerprint sensor according to an embodiment ofthe invention;

FIG. 3 shows a top view of a light filter layer according to anembodiment of the invention;

FIG. 4 shows a top view of a light filter layer according to anotherembodiment of the invention;

FIG. 5 shows a top view of a light filter layer according to anotherembodiment of the invention;

FIG. 6 shows a top view of a light filter layer according to anotherembodiment of the invention;

FIG. 7 shows a top view of a light filter layer according to anotherembodiment of the invention; and

FIG. 8 shows a manufacturing method of the sensing module of the opticalfingerprint sensor according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carryingout the invention. This description is made for the purpose ofillustrating the general principles of the invention and should not betaken in a limiting sense. The scope of the invention is best determinedby reference to the appended claims.

FIG. 2 shows an optical fingerprint sensor 100 according to anembodiment of the invention. The optical fingerprint sensor 100 includesa sensing module 10 and a panel module 50. The sensing module 10 isdisposed under the panel module 50. The optical fingerprint sensor 100is manufactured by attaching the sensing module 10 to the panel module50. In the embodiment, the sensing module 10 is attached to the panelmodule 50 via an adhesive (not shown).

The panel module 50 includes a cover glass 60 and a light-emitting layer70. The light-emitting layer 70 includes a light-emitting arrayincluding a plurality of light-emitting units Cell. In order to simplifythe description, the configuration of the light-emitting units Cell inthe light-emitting layer 70 will be omitted. The cover glass 60 isdisposed above the light-emitting layer 70 so as to cover thelight-emitting array. Each light-emitting unit Cell has a light sourcezone (i.e. a non-transparent zone) Z1 and a transparent zone Z2, and thelight source zone Z1 includes a light-emitting device 80. Thelight-emitting device 80 emits the light 90, and the light 90 willpenetrate the cover glass 60 to illuminate the finger 40. In someembodiments, the panel module 50 is an organic light-emitting diode(OLED) panel, and the light-emitting device 80 is an organiclight-emitting diode (OLED). In some embodiments, the panel module 50 isa micro-LED panel, and the light-emitting device 80 is a micro-LED.

The sensing module 10 includes a light sensing layer (or light receivinglayer) 20 and a light filter layer 30. The light filter layer 30 of thesensing module 10 may be attached to the light-emitting layer 70 of thepanel module 50 via an adhesive. The light sensing layer 20 includes aplurality of photo detectors 25 arranged in a sensing array. In oneembodiment, the photo detectors 25 are photo diodes. In an X direction,each photo detector 25 has the same length. Furthermore, the lightdetectors 25 are spaced evenly.

The light filter layer 30 is made of light blocking (e.g.,light-shielding, light-absorbing or opaque) materials. The light filterlayer 30 has a plurality of collimators 35. Light (e.g., the reflectedlight 95) passes through the collimators 35 of the light filter layer 30to reach the light sensing layer 20 disposed under the light filterlayer 30. In some embodiments, each collimator 35 forms an opening inthe light filter layer 30, so that the light can pass from one side tothe other side of the light filter layer 30 through the collimators.Moreover, each collimator 35 has the same shape and size of opening(e.g., an diameter L1). In some embodiments, the diameter L1 of thecollimators 35 is between 1 and 20 micrometers (μm). In addition, theratio of the diameter L1 to a height H1 of the collimators 35 is between1:3 and 1:30.

In the light filter layer 30, the collimators 35 are divided into aplurality of collimator groups GP. The collimator groups GP arerespectively aligned with the photo detectors 25, each of the collimatorgroups GP is corresponding to one of the photo detectors 25, and eachcollimator group GP has the same number of collimators 35. Compared tothe conventional optical fingerprint sensors, in the optical fingerprintsensor 100 of FIG. 2 of the present invention, the total number of thecollimators 35 is greater than that of the photo detectors 25, and oneof the photo detectors 25 can receive the reflected light passingthrough several collimators 35 within the corresponding collimator groupGP. Therefore, when manufacturing the sensing module 10, the collimators35 need not to be aligned with the photo detectors 25 while thecollimator groups GP have to be respectively aligned with the photodetectors 25. Furthermore, when the panel module 50 is being attached tothe sensing module 10, the photo detectors 25 of the sensing module 10need not to be aligned with the light-emitting units Cell of the panelmodule 50. Therefore, in the present invention, the manufacturingprocess of the optical fingerprint sensor 100 is simplified and theyield is increased.

In FIG. 2, when the finger 40 contacts the optical fingerprint sensor100, the light-emitting devices 80 in the light source zones Z1 of thelight-emitting units Cell emit the light 90, and the light 90 penetratesthe cover glass 60 to illuminate the finger 40. The reflected light 95reflected from the surface of the finger 40 passes through thecollimators 35 of the light filter layer 30 of the sensing module 10, toreach the light sensing layer 20. The photo detectors 25 of the lightsensing layer 20 will sense the reflected light 95. The reflected light95 reflected by the fingerprint ridges and the fingerprint valleys ofthe finger 40 will have different amounts of energy or wavelengths.After receiving the reflected light 95, each photo detector 25 convertsthe received reflected light 95 into a sensing output, and provides thesensing output to a processor (not shown) or other subsequent circuits,so as to obtain fingerprint information of the finger 40.

The number of photo detectors 25 of the light sensing layer 20 may be aninteger multiple of the number of light-emitting units Cell of thelight-emitting layer 70. In some embodiments, some photo detectors 25may be partially covered by the light source zones Z1 of thelight-emitting units Cell, and such photo detectors 25 may receive thereflected light 95 emitted by the two adjacent light-emitting units Celldisposed above them and reflected from the finger 40. Since each photodetector 25 is disposed under the multiple collimators 35 in thecorresponding collimator group GP, when some of the collimators 35disposed above the photo detector 25 are covered by the light sourcezones Z1 of the light-emitting units Cell disposed above the photodetector 25, the photo detector 25 can receive the reflected light 95through the other collimators 35 of the collimator group GP that are notentirely covered by the light source zones Z1. Thus, according to thesensing output provided by each photo detector 25, the opticalfingerprint sensor 100 can obtain the fingerprint information of thefinger 40.

FIG. 3 shows a top view of a light filter layer 30A according to anembodiment of the invention. In the light filter layer 30A, a pluralityof collimators 35 are divided into a plurality of collimator groups GP1.The collimator groups GP1 are arranged in a collimator group array, andthe photo detectors 25 are arranged in a sensing array. The collimatorgroups GP1 of the collimator group array are respectively aligned withthe photo detectors 25 of the sensing array, and each of the collimatorgroups GP1 is corresponding to one of the photo detectors 25 of thelight sensing layer 20 of FIG. 2. In other words, each collimator groupGP1 is disposed above the corresponding photo detector 25. In FIG. 3,each collimator group GP1 comprises seven collimators 35 arranged in aspecific pattern. In the embodiment, the specific pattern includes asingle center collimator 35 a arranged in the center of the specificpattern and a plurality of peripheral collimators 35 b_1-35 b_6surrounding the single center collimator 35 a. In the embodiment, thenumber of the peripheral collimator 35 b_1-35 b_6 is 6, and thearrangement of the peripheral collimator 35 b_1-35 b_6 forms a hexagon.In some embodiments, the distance D1 between two adjacent collimators 35in each collimator group GP1 is identical. That is, the collimators 35in each collimator group GP1 are spaced evenly, and the distance D1 fromthe center collimator 35 a to each of the peripheral collimators 35b_1-35 b_6 is identical (i.e., the peripheral collimators 35 b_1-35 b_6are equidistant from the center collimator 35 a), and the distance D1between any two adjacent ones of the collimators 35 b_1-35 b_6 is alsoidentical. In some embodiments, the distance D1 is greater than or equalto 3 micrometers (μm). Moreover, the distance D2 between the twoperipheral adjacent collimators 35 separately located at two adjacentcollimator groups GP1 is smaller than the distance D1 between the twoadjacent collimators 35 located at the same collimator group GP1, i.e.D2<D1. In some embodiments, the diameter (i.e. L1 in FIG. 2) of thecollimators 35 is greater than the distance D1 between the two adjacentcollimators 35.

FIG. 4 shows a top view of a light filter layer 30B according to anotherembodiment of the invention. In the light filter layer 30B, a pluralityof collimator 35 are divided into a plurality of collimator groups GP1and a plurality of collimator groups GP1_R. The collimator groups GP1and GP1_R are arranged in a collimator group array, and the photodetectors 25 are arranged in a sensing array. The collimator groups GP1and GP1_R of the collimator group array are respectively aligned withthe photo detectors 25 of the sensing array, and each of the collimatorgroups GP1 and GP1_R is corresponding to one of the photo detectors 25of the light sensing layer 20 of FIG. 2. In other words, each collimatorgroup GP1 or GP1_R is disposed above the corresponding photo detector25. In addition, in each row and each column of the collimator grouparray, the collimator groups GP1 and the collimator groups GP1_R arealternately arranged. Thus, each collimator group GP1 are adjacent tofour of the collimator groups GP1_R on the four sides, and similarly,each collimator group GP1_R are adjacent to four of the collimatorgroups GP1 on the four sides. In the embodiment, a second specificpattern of the collimator groups GP1_R can be obtained by clockwiserotating a first specific pattern of the collimator groups GP1 by 90degrees. For example, in each collimator group GP1, the peripheralcollimator 35 b_6, the center collimator 35 a and the peripheralcollimator 35 b_3 are disposed on the same straight line along the Xdirection. In each collimator group GP1_R, the peripheral collimator 35b_3, the center collimator 35 a and the peripheral collimator 35 b_6 aredisposed on the same straight line along the Y direction. Moreover, thedistance D1 between two adjacent collimators 35 in each collimator groupGP1_R and each collimator group GP1 is identical. In some embodiments,the distance D1 is greater than or equal to 3 micrometers (μm). Itshould be noted that the distance D2 of the two adjacent peripheralcollimators 35 separately located at two adjacent collimator groups GP1and GP1_R is greater than or equal to the distance D1 between the twoadjacent collimators 35 located at the same collimator group GP1 orGP1_R, i.e., D2≥D1. In some embodiments, the diameter of the collimator35 (i.e. L1 in FIG. 2) is greater than the distances D1 and D2.

FIG. 5 shows a top view of a light filter layer 30C according to anotherembodiment of the invention. In the light filter layer 30C, a pluralityof collimators 35 are divided into a plurality of collimator groups GP2.In addition, the collimator groups GP2 are arranged in a collimatorgroup array, and the photo detectors 25 are arranged in a sensing array.The collimator groups GP2 of the collimator group array are respectivelyaligned with the photo detectors 25 of the sensing array, and each ofthe collimator groups GP2 is corresponding to one of the photo detectors25 of the light sensing layer 20 of FIG. 2. In other words, eachcollimator group GP2 is disposed above the corresponding photo detector25. In FIG. 5, each collimator group GP2 includes five collimators 35arranged in a specific pattern. Moreover, a single center collimator 35a is arranged at the center of the specific pattern and is surrounded bya plurality of peripheral collimators 35 b_1-35 b_4. In the embodiment,the number of the peripheral collimators 35 b_1-35 b_4 is 4, and theperipheral collimators 35 b_1-35 b_4 are arranged to form aquadrilateral. In each collimator group GP2, the distance D3 from thecenter collimator 35 a to each of the peripheral collimators 35 b_1-35b_4 is identical (i.e. the peripheral collimators 35 b_1-35 b_4 areequidistant from the center collimator 35 a), and the distance D3 abetween two adjacent ones of the peripheral collimators 35 b_1-35 b_4 isalso identical, where D3 a≥D3. In some embodiments, the distance D3 isgreater than or equal to 3 micrometers (μm). In some embodiments, thedistance D4 between the two adjacent peripheral collimators 35separately located at two adjacent collimator groups GP2, is greaterthan or equal to the distance D3 between the two adjacent collimators 35located at the same collimator group GP2, i.e. D4≥D3. In someembodiments, the diameter (i.e. L1 in FIG. 2) of the collimator 35 isgreater than the distances D3 and D4.

FIG. 6 shows a top view of the light filter layer 30D according toanother embodiment of the invention. In the light filter layer 30D, aplurality of collimators 35 are divided into a plurality of collimatorgroups GP3 and a plurality of collimator groups GP3_R. The collimatorgroups GP3 and GP3_R are arranged in a collimator group array, and thephoto detectors 25 are arranged in a sensing array. The collimatorgroups GP3 and GP3_R of the collimator group array are respectivelyaligned with the photo detectors 25 of the sensing array, and each ofthe collimator groups GP3 and GP3_R is corresponding to one of the photodetectors 25 of the light sensing layer 20 of FIG. 2. Each of thecollimator groups GP3 and GP3_R is disposed above the correspondingphoto detector 25. In addition, in each row of the collimator grouparray, the collimator groups GP1 and the collimator groups GP1_R arearranged alternately, and in each column of the collimator group array,the same collimator groups GP3 or GP3_R are arranged. For example, thecollimator groups GP3 are arranged in the first column COL1 and thethird column COL3. The collimator groups GP3_R are arranged in thesecond column COL2 and the fourth column COL4. In the embodiment, afirst specific pattern of the collimator groups GP3 is a triangle formedby three collimators 35. In the embodiment, the first specific patternin the collimator groups GP3 does not have a center collimator. Inaddition, a second specific pattern of the collimator groups GP3_R isobtained by rotating the first specific pattern of the collimator groupsGP3 by 180 degrees. Furthermore, the distance D5 between any twoadjacent ones of the collimators 35 in each collimator group GP3 andeach collimator group GP3_R is identical. In some embodiments, thedistance D5 is greater than or equal to 3 micrometers (μm). In theembodiment, the distance D6 between the two adjacent collimators 35separately located at two adjacent collimator groups GP3 and/or GP3_R,is greater than or equal to the distance D5 between two adjacentcollimators 35 in the same collimator group GP3 or GP3_R, i.e. D6≥D5. Insome embodiments, in each column of the collimator group array, thecollimator groups GP3 and GP3_R are arranged alternately, and in eachrow of the collimator group array, the same collimator groups GP3 orGP3_R are arranged. In some embodiments, the diameter (i.e. L1 in FIG.2) of the collimators 35 is greater than the distances D5 and D6.

FIG. 7 shows a top view of a light filter layer 30E according to anotherembodiment of the invention. In the light filter layer 30E, a pluralityof collimators 35 are divided into a plurality of collimator groups GP4and a plurality of collimator groups GP4_R. The collimator groups GP4and GP4_R are arranged in a collimator group array, and the photodetectors 25 are arranged in a sensing array. The collimator groups GP4and GP4_R of the collimator group array are respectively aligned withthe photo detectors 25 of the sensing array, and each of the collimatorgroups GP4 and GP4_R is corresponding to one of the photo detectors 25of the light sensing layer 20 of FIG. 2. Each of the collimator groupsGP4 and GP4_R is disposed above the corresponding photo detector 25.Moreover, in each row and each column of the collimator group array, thecollimator groups GP4 and the collimator groups GP4_R are alternatelyarranged. Thus, each collimator group GP4 is adjacent to four of thecollimator groups GP4_R on the four sides, and each collimator groupGP4_R is adjacent to four of the collimator groups GP4 on the foursides. Each collimator group GP4 comprises four collimators 35 arrangedin a first specific pattern of quadrilateral. In the embodiment, thefirst specific pattern of the collimator groups GP4 does not have acenter collimator. In addition, a second specific pattern of thecollimator groups GP4_R is obtained by clockwise rotating the firstspecific pattern of the collimator groups GP4 by 45 degrees.Furthermore, the distance D7 between two adjacent collimators 35 in eachof the collimator groups GP4 and each of the collimator groups GP4_R isidentical. In some embodiments, the distance D7 is greater than or equalto 3 micrometers (μm). In FIG. 7, the distance D8 between the twoadjacent collimators 35 separately located at two adjacent collimatorgroups GP4 and GP4_R may be equal to or greater than the distance D7between the two adjacent collimators 35 located at the same collimatorgroup GP4 or GP4_R, i.e. D8≥D7. In some embodiments, the diameter (i.e.L1 in FIG. 2) of the collimators 35 is greater than the distances D7 andD8.

FIG. 8 shows a manufacturing method of the sensing module 10 of theoptical fingerprint sensor 100 according to an embodiment of theinvention. First, in step S810, a plurality of photo detectors 25 areformed in the light sensing layer 20, and the photo detectors 25 arearranged as a sensing array. Next, in step S820, a plurality ofcollimators 35 are formed in the light filter layer 30. In someembodiments, the collimators 35 of the light filter layer 30 may bedivided into a plurality of collimator groups with the same pattern,such as the collimator groups GP1 of the light filter layer 30A in FIG.3 and the collimator groups GP2 of the light filter layer 30C in FIG. 5.The collimator groups in the light filter layer 30 are arranged in acollimator group array. In some embodiments, the collimators 35 of thelight filter layer 30 may be divided into a plurality of firstcollimator groups with a first pattern and a plurality of secondcollimator groups with a second pattern, such as the collimator groupsGP1 and GP1_R of the light filter layer 30B in FIG. 4, the collimatorgroups GP3 and GP3_R of the light filter layer 30D in FIG. 6 and thecollimator groups GP4 and GP4_R of the light filter layer 30E in FIG. 7.The first and second collimator groups in the light filter layer 30 arearranged in a collimator group array. In some embodiments, the number ofthe photo detectors 25 in the sense array is the same as the number ofthe collimator groups in the collimator group array. In someembodiments, the order of steps S810 and S820 may be reversed.

In some embodiments, in step S820, the second collimator groups with thesecond pattern is obtained by rotating the first collimator groups withthe first pattern. In addition, in step S820, the first collimatorgroups and the second collimator groups are alternately arranged in eachrow and/or each column of the collimator group array.

Next, in step S830, the light sensing layer 20 is attached to the lightfilter layer 30 in such a way that the light filter layer 30 ispositioned above the light sensing layer 20, and the collimator grouparray of the light filter layer 30 is aligned with the sensing array ofthe light sensing layer 20. In other words, each photo detector 25 ofthe sensing array corresponds to one of the collimator groups in thecollimator group array, and is aligned with the corresponding collimatorgroup.

In the optical fingerprint sensors of the embodiments of the invention,each photo detector corresponds to a plurality of collimators in thecorresponding collimator group, and therefore, in the process ofmanufacturing the sensing module, the photo detectors are respectivelyaligned with the corresponding collimator groups without considering thepositional relationship between the photo detectors and the individualcollimators. Furthermore, when attaching the sensing module to the panelmodule, neither does it need to the positional relationship between thesensing module and the panel module since the photo detectors need notto be aligned with the light-emitting units. Therefore, themanufacturing process of the optical fingerprint sensor will besimplified and the yield can be improved.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited to the disclosed embodiments. On the contrary, it isintended to cover various modifications and similar arrangements (aswould be apparent to those skilled in the art). Therefore, the scope ofthe appended claims should be accorded the broadest interpretation so asto encompass all such modifications and similar arrangements.

What is claimed is:
 1. A manufacturing method of a sensing module for anoptical fingerprint sensor, comprising: forming a plurality of photodetectors in a light sensing layer, wherein the photo detectors arearranged in a sensing array; forming a plurality of collimators in alight filter layer, wherein the collimators are divided into a pluralityof collimator groups respectively corresponding to the photo detectorsand the collimator groups are arranged in a collimator group array; andattaching the light sensing layer to the light filter layer so that thelight filter layer is disposed above the light sensing layer and thecollimator group array of the light filter layer is aligned with thesensing array of the light sensing layer, wherein the collimator groupsof the collimator group array are respectively corresponding to thephoto detectors of the sensing array and each of the collimator groupscorresponds to one of the photo detectors; wherein the collimators ineach of the collimator groups are arranged in a specific pattern anddisposed above the corresponding photo detector.
 2. The manufacturingmethod as claimed in claim 1, wherein in each of the collimator groups,a distance between any two adjacent ones of the collimators isidentical.
 3. The manufacturing method as claimed in claim 1, whereineach of the collimator groups comprise the same number of collimatorsarranged in the same specific pattern.
 4. The manufacturing method asclaimed in claim 1, wherein each of the collimator groups comprise acenter collimator and a plurality of peripheral collimators surroundingthe center collimator.
 5. The manufacturing method as claimed in claim4, wherein the peripheral collimators are equidistant from the centercollimator.
 6. The manufacturing method as claimed in claim 1, whereinthe ratio of a diameter to height of the collimators is between 1:3 and1:30 and the diameter of the collimators is between 1 and 20micrometers.
 7. A manufacturing method of a sensing module for anoptical fingerprint sensor, comprising: forming a plurality of photodetectors in a light sensing layer, wherein the photo detectors arearranged in a sensing array; forming a plurality of collimators in alight filter layer, wherein the collimators are divided into a pluralityof first collimator groups with a first pattern and a plurality ofsecond collimator groups with a second pattern, and the first and secondcollimator groups are arranged in a collimator group array; andattaching the light sensing layer to the light filter layer so that thelight filter layer is disposed above the light sensing layer and thecollimator group array of the light filter layer is aligned with thesensing array of the light sensing layer, wherein the first and secondcollimator groups are respectively aligned with the photo detectors andeach of the first and second collimator groups corresponds to one of thephoto detectors; wherein the total number of the first and secondcollimator groups is equal to the number of the photo detectors.
 8. Themanufacturing method as claimed in claim 7, wherein in each of the firstand second collimator groups, a distance between any two adjacent onesof the collimators is identical.
 9. The manufacturing method as claimedin claim 7, wherein the second pattern is obtained by rotating the firstpattern by a specific angle.
 10. The manufacturing method as claimed inclaim 7, wherein the step of forming the collimators in the light filterlayer further comprises: alternately arranging the first collimatorgroups and the second collimator groups in each row or each column ofthe collimator group array.
 11. The manufacturing method as claimed inclaim 7, wherein each of the first and second collimator groupscomprises a center collimator and a plurality of peripheral collimatorssurrounding the center collimator.
 12. The manufacturing method asclaimed in claim 11, wherein the peripheral collimators are equidistantfrom the center collimator.
 13. The manufacturing method as claimed inclaim 7, wherein the ratio of a diameter to height of the collimators isbetween 1:3 and 1:30 and the diameter of the collimators is between 1and 20 micrometers.